SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78805d74080d0060750e23d936721dc91e417b710513cc9261c5258e6d2f8515' 
  AND token = '0JhqZjxoEzAqmSsheMhwas3RkzDSgXQQrCCXhuyGYgY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}